Jump to content

Help? Odd matrix on Led Zeppelin II (RL version)-- "MOMMA"?


Recommended Posts

I just picked up an excellent copy of this album, and at the store I just noticed the "RL" in the matrix so I grabbed it. At home, looking more closely, I found an oddity that I did not find reference to in a search.

Side 1 (wide runnoff): ST-A-69171 - (long space) C RL SS W CH3P(?) MOMMA S (with RC inside) BP (upside down) AT

Side 2 (narrow runnoff): ST-A- 69172-B CH3P(?) AT RL SS W S (with RC).

Both sides have what looks like an upside down L with an E next to it.

The "MOMMA" throws me-- anyone know what it means or relates to?

Link to comment
Share on other sites

I'll take a guess...a person working in the record pressing plant.

The Vinyl Manufacturing Process

The first part of the Vinyl manufacturing process is Mastering / Cutting the Lacquer. This is where we convert your music / audio to analogue signals. The Lathe cuts a spiral groove via a vibrating cutting stylus. The precise groove is cut across an aluminium disc covered with a plastic coating (the lacquer) and is cut at an exact speed of 33 1/3 or 45rpm.

The Lathe looks a bit like a large record player that rotates backwards. This is simply a phonograph pickup in reverse. This part of the process is managed by an experienced Engineer who will adjust the EQ and compression to ensure a good groove. Each lacquer is single sided so 2 lacquers must be cut for a two-sided record.

We also offer DMM processing (Direct Metal Mastering) which is where we use metal/copper plates for cutting the grooves into. The galvanic procedure that follows is not as complicated as the process for lacquers and we can make stampers directly from these plates.

Vinyl Lacquer Cutting

The Lacquer cutting process is a very technical part of the Vinyl manufacturing process and for this reason, some of our customers prefer to supply us their own lacquers for which they have personally attended the lacquer cut, with the engineer, at the studio. It is not a problem for you to supply us lacquers but please let us know in advance.

It is possible to engrave 60 characters of letters & numbers into the centre of the A & B side of the Vinyl and this information is done at the cutting stage and needs to be specified at the order form completion stage >> Ordering Vinyl records <<. There is a small additional charge for doing this.

Vinyl Acetates


Acetates (or Dub-Plate) is a one-off disk which is playable on a turntable. Acetates are softer than pressed Vinyl so they're only good for about 40-50 plays or so before the sound on them decays noticeably. Acetates cost extra and don't forget additional costs if you need mixing done to your music in our studio before we commit your tune to the dub plate.

Dub plates are a cost effective way for you to test a new track or to try out experimental ideas that won't always make it onto the "finished" Vinyl.

Vinyl Stampers

Next up is the Processing of the Metalwork which is the process of growing stampers through a galvanic process. The stampers are used to physically press the records.

The lacquer is sprayed with a silver solution to make it a good conductor of electricity. This is then placed in a bath containing a nickel suphamate solution and an electric current is passed through. Through an electro-plating process, nickel particles are attracted to the surface of the lacquer. This nickel layer is physically removed off of the lacquer and is sometimes referred to as the Father (or 1st Negative).


These Stampers are used for the actual pressing of the records. Since the Mother is made of metal (unlike the delicate lacquer original), its durability means it can be used for re-growing further stampers, all identical with the first, avoiding having to repeat much of the metalwork processing.

The 2 thin metal stamper plates ( Side A and Side B ) are fitted to the Vinyl press above and below a puck (or biscuit) of Vinyl and the labels are put on the top side and under side of the puck. This is squashed between two heated moulds under hydraulic pressure. Several Vinyl's will be pressed up and once these are trimmed and cooled, you have your Test Pressings. These will be listened to ensure all is OK and then sent to you to thoroughly check. If you are happy that there are no scratches, crackles or pops and approve the TP's, we can then go ahead with the main run.

While all this is going on, your record labels and printed sleeves will be printing at our printers. When the labels arrive in, they are 'baked' to remove the moisture and held in storage along with the Sleeves until the TP's are approved and we are ready to go into mass production.

Once the Vinyl is pressed (with the labels), the records are hand packed into the chosen sleeves or Disco bags, boxed and ready to be delivered.

Link to comment
Share on other sites


This topic is now archived and is closed to further replies.

  • Create New...